Electrical switch



sept. 19, 1939. I H, J, MAES 2,173,284

ELECTRICAL SWITCH I Filed June '7. 1937 @llo/nys Patented Sept. `19, 1939 UNITED STATES.

PATENT OFFICE ELECTRICAL SWITCH Application June 7, 1937, Serial No. 146,842

1 Claim.

This invention relates to an electrical switch. More particularly the invention is concerned with the type of switch wherein at least one pair of contacts are mounted for relative movement 5 transversely of the current path between the contacts for making and interrupting an electrical circuit, and wherein at least one of the contacts is arranged to reciprocate along lines substantially normal to the direction of relative movement.

It will be understood that in such a switch the reciprocable contact is normally yieldably urged toward a, position at which engagement between the contacts will be effected during the relative movement thereof and the engagement will be at a pressure sulcient to assure suitable electrical contact but insuilicient to introduce undue friction or enough friction seriously to interfere with the relative movement.

zo The invention includes among its objects the provision of a novel and an improved switch of the type mentioned, and a novel contact for such switch which is longitudinally reciprocable but which is held against rotation about its longitudinal axis, which is economical to make, which cal views, 4respectively showing fragments of plan and transverse cross sections of a switch embodying the features of the invention;

Fig. 3 is a fragmentary cross section through one of the novel contacts with the contact member shown partially in cross section and partial- 1y in side elevation;

Fig. 4 is a view similar to that shown in Fig. 3, but looking in the direction of the arrows 4-4 of Fig. 3; and

Fig. 5 is a cross section taken substantially along Vthe lines 5--5 of Fig. 4.

As diagrammatically illustrated in Figs. 1 and 2, an electrical switch of the type referredl to hereinbefore comprises a pair of plate-like or other suitable contact carrying members II and I2 which are arranged in spaced relation for relative movement, for example, about a common axis of a post or shaft I3. The direction of relative movement is substantially parallel to the members II and I2, or, stated in slightly diierent terms, the direction of relative movement is 5 transversely of the electrical current path between the switch elements. One of the contact carrying members, for example the contact carrying member I2, is provided with one or more contact members I4 on its surface, facing the 10 other contact carrying member, and each contact member I4 is electrically associated with a binding post or terminal I5 at the opposite surface of the contact carrying member I2 to facilitate connecting each contact member I4 15 in circuit by, for example, a conducting lead I6.

It will be understood by those skilled in the art to which this invention pertains, that a contact member for each of the contact members I4 is correspondingly arranged on the con- 20 tact carrying member II for engaging and disengaging with the contact members I4, respectively, during the relative movement of the contact carrying members II and I2.

'Ihe contact members for engaging the mem- 25 bers I4 have heretofore beenprovided in the form of elongated tubular or cylindrical members having enlarged, substantially flat heads at the contact ends. The Shanks of those contact members were slidably and yieldably arranged 30 in apertures through an insulating member or strip I1 suitably secured, as at I8, to the contact carrying member II. When so arranged, the contact heads faced the contact carrying member I2 and normally were yieldably urged 35 to positions adjacent the surface thereof carrying the contact members I4.

During relative movement of the contact members II and I2 transversely of the electrical current path between such contact members, the 40 Contact heads and the corresponding contacts I4 would slidingly engage one another, the contact heads yielding to permit such sliding engagement. In such operation, the elongated contact member would rock or oscillate about its longi- 45 tudinal axis, thus twisting and thereby straining the lead conductor and its connection with the contact member, and sometimes breaking the lead or its connection with the contact member. 50

In order to overcome that difculty and to provide a more ecient contact, I employ for the reciprocable contact, as shown in Figs. 3 to 5, an elongated strip I9 having at one end a flat head portion 2| of contact material of greater 55 lil 2 arrasar;

width than the strip shanlr, and at its oppo= site end a connection terminal portion 22. The terminal portion 22 may be provided with an aperture 23 therein to facilitate connecting the contact in circuit by a suitable lead conductor 24. The head portion l of the contact is pref erably hardened by hammering, and is formed with a line contact portion 25 and with beveled ends 2li.

For slidably mounting such a contact to prevent rotation or rocking thereof, l provide a bushing of tubular form having a limiting external flange El intermediate its ends, a passage dit leading from one end of the bushing into communication with a larger passage 2@ at the other end of the bushing and providing an internal shoulder iii intermediate the ends of and inside the bushing, and a pair of slots or grooves l2 extending longitudinally oi the bushing at diametrical sides thereof in the walls of the passage iii.

in assembling the novel Contact, a coil spring 33 is arranged about the shank oi the elongated contact with one end. abutting the contact head portion fil. The other end oi the shank is inserted in the outer end of the passage 28 and arranged in the guide slots 32. The elongated contact is then moved into the bushing, bringing the end of the spring 33 opposite the head portion 2i into abutting relation with the ilange 2li. By compressing the spring, the terminal end of the elongated contact may be projected through the passage E@ and outside of the bushing whereby to facilitate bending the contact, as at 3d, to cause the terminal portion Z2 to cooperate with the internal shoulder ill in holding the spring urged elongated contact and bushing in assembled relationship.

.One or more such assembled contacts, depending upon the number of Contact members Ml employed in the switch, are secured to the insulating member il by forcing that end of each bushing including the large passage Z9 into an aperture in the insulating member, the external ilange il' serving to limit the movement of the bushing during that assembly operation. In thus as. sembling the contact and mounting means, l'. arrange the contact head with its line contact portion 2b extending in the direction of relative movement transversely of the electrical current path so that the beveled ends 2li may serve as cam surfaces engageable with the corresponding contact lll to compress 'the spring 33 whereby to permit sliding contact of linear characteristics between corresponding contact members during the relative movement of the contact carrying members.

Thus i secure the electrical advantages of line Contact and in addition, with a minimum of friction, a rm wiping electrical contact. .The slots or grooves serve not only to guide each elongated contact in its reciprocable movement, but also to prevent it from rotating or rocking about its longitudinal axis. In that manner twisting strains on the leads 2d and their connections with the contact members are minimized, if not entirely eliminated, with the advantageous result of durable connections of the novel contacts in circuit.

While have described a speciiic embodiment of the invention, it will be understood that the invention is not limited to the precise details set forth hereinbeiore, but that many changes and modifications may be made without departing from the spirit or scope oi the following claim.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

An electric switch comprising a contact, a circuit closure meanscooperating therewith comprising a bushing movable in a direction substantially transverse the direction of ow of current through the switch, said bushing having internal longitudinal slots and an internal annular shoulder, an external flange on said bushing inter mediate the ends thereof constituting a limiting stop for the bushing upon inserting the portion thereof at one side of the flange in an apertured support, a conductor member of strap form slidably disposed .in said slots and provided with a shouldered Contact head at one end, a spring disposed between said head and said external ange for urging said conductor member and Contact head in a direction axially of the bushing for effecting engagement of said head with said contact, and a conductor terminal at the other end of said conductor member comprising an integral portion of the latter offset from the plane of the remaining portion thereof and arranged to abut said internal shoulder for limiting axial movement oi the conductor member by said spring.

HARRY J. NIABS.

Cil 

